(function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
        typeof define === 'function' && define.amd ? define(['exports'], factory) :
            (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.Redux = {}));
}(this, (function (exports) {
    'use strict';

// Inlined version of the `symbol-observable` polyfill
    var $$observable = (function () {
        return typeof Symbol === 'function' && Symbol.observable || '@@observable';
    })();

    /**
     * These are private action types reserved by Redux.
     * For any unknown actions, you must return the current state.
     * If the current state is undefined, you must return the initial state.
     * Do not reference these action types directly in your code.
     */
    var randomString = function randomString() {
        return Math.random().toString(36).substring(7).split('').join('.');
    };

    var ActionTypes = {
        INIT: "@@redux/INIT" + randomString(),
        REPLACE: "@@redux/REPLACE" + randomString(),
        PROBE_UNKNOWN_ACTION: function PROBE_UNKNOWN_ACTION() {
            return "@@redux/PROBE_UNKNOWN_ACTION" + randomString();
        }
    };

    /**
     * @param {any} obj The object to inspect.
     * @returns {boolean} True if the argument appears to be a plain object.
     */
    function isPlainObject(obj) {
        if (typeof obj !== 'object' || obj === null) return false;
        var proto = obj;

        while (Object.getPrototypeOf(proto) !== null) {
            proto = Object.getPrototypeOf(proto);
        }

        return Object.getPrototypeOf(obj) === proto;
    }

// Inlined / shortened version of `kindOf` from https://github.com/jonschlinkert/kind-of
    function miniKindOf(val) {
        if (val === void 0) return 'undefined';
        if (val === null) return 'null';
        var type = typeof val;

        switch (type) {
            case 'boolean':
            case 'string':
            case 'number':
            case 'symbol':
            case 'function': {
                return type;
            }
        }

        if (Array.isArray(val)) return 'array';
        if (isDate(val)) return 'date';
        if (isError(val)) return 'error';
        var constructorName = ctorName(val);

        switch (constructorName) {
            case 'Symbol':
            case 'Promise':
            case 'WeakMap':
            case 'WeakSet':
            case 'Map':
            case 'Set':
                return constructorName;
        } // other


        return type.slice(8, -1).toLowerCase().replace(/\s/g, '');
    }

    function ctorName(val) {
        return typeof val.constructor === 'function' ? val.constructor.name : null;
    }

    function isError(val) {
        return val instanceof Error || typeof val.message === 'string' && val.constructor && typeof val.constructor.stackTraceLimit === 'number';
    }

    function isDate(val) {
        if (val instanceof Date) return true;
        return typeof val.toDateString === 'function' && typeof val.getDate === 'function' && typeof val.setDate === 'function';
    }

    function kindOf(val) {
        var typeOfVal = typeof val;

        {
            typeOfVal = miniKindOf(val);
        }

        return typeOfVal;
    }

    /**
     * Creates a Redux store that holds the state tree.
     * The only way to change the data in the store is to call `dispatch()` on it.
     *
     * There should only be a single store in your app. To specify how different
     * parts of the state tree respond to actions, you may combine several reducers
     * into a single reducer function by using `combineReducers`.
     *
     * @param {Function} reducer A function that returns the next state tree, given
     * the current state tree and the action to handle.
     *
     * @param {any} [preloadedState] The initial state. You may optionally specify it
     * to hydrate the state from the server in universal apps, or to restore a
     * previously serialized user session.
     * If you use `combineReducers` to produce the root reducer function, this must be
     * an object with the same shape as `combineReducers` keys.
     *
     * @param {Function} [enhancer] The store enhancer. You may optionally specify it
     * to enhance the store with third-party capabilities such as middleware,
     * time travel, persistence, etc. The only store enhancer that ships with Redux
     * is `applyMiddleware()`.
     *
     * @returns {Store} A Redux store that lets you read the state, dispatch actions
     * and subscribe to changes.
     */

    function createStore(reducer, preloadedState, enhancer) {
        var _ref2;

        if (typeof preloadedState === 'function' && typeof enhancer === 'function' || typeof enhancer === 'function' && typeof arguments[3] === 'function') {
            throw new Error('It looks like you are passing several store enhancers to ' + 'createStore(). This is not supported. Instead, compose them ' + 'together to a single function. See https://redux.js.org/tutorials/fundamentals/part-4-store#creating-a-store-with-enhancers for an example.');
        }

        if (typeof preloadedState === 'function' && typeof enhancer === 'undefined') {
            enhancer = preloadedState;
            preloadedState = undefined;
        }

        if (typeof enhancer !== 'undefined') {
            if (typeof enhancer !== 'function') {
                throw new Error("Expected the enhancer to be a function. Instead, received: '" + kindOf(enhancer) + "'");
            }

            return enhancer(createStore)(reducer, preloadedState);
        }

        if (typeof reducer !== 'function') {
            throw new Error("Expected the root reducer to be a function. Instead, received: '" + kindOf(reducer) + "'");
        }

        var currentReducer = reducer;
        var currentState = preloadedState;
        var currentListeners = [];
        var nextListeners = currentListeners;
        var isDispatching = false;

        /**
         * This makes a shallow copy of currentListeners so we can use
         * nextListeners as a temporary list while dispatching.
         *
         * This prevents any bugs around consumers calling
         * subscribe/unsubscribe in the middle of a dispatch.
         */

        function ensureCanMutateNextListeners() {
            if (nextListeners === currentListeners) {
                nextListeners = currentListeners.slice();
            }
        }

        /**
         * Reads the state tree managed by the store.
         *
         * @returns {any} The current state tree of your application.
         */


        function getState() {
            if (isDispatching) {
                throw new Error('You may not call store.getState() while the reducer is executing. ' + 'The reducer has already received the state as an argument. ' + 'Pass it down from the top reducer instead of reading it from the store.');
            }

            return currentState;
        }

        /**
         * Adds a change listener. It will be called any time an action is dispatched,
         * and some part of the state tree may potentially have changed. You may then
         * call `getState()` to read the current state tree inside the callback.
         *
         * You may call `dispatch()` from a change listener, with the following
         * caveats:
         *
         * 1. The subscriptions are snapshotted just before every `dispatch()` call.
         * If you subscribe or unsubscribe while the listeners are being invoked, this
         * will not have any effect on the `dispatch()` that is currently in progress.
         * However, the next `dispatch()` call, whether nested or not, will use a more
         * recent snapshot of the subscription list.
         *
         * 2. The listener should not expect to see all state changes, as the state
         * might have been updated multiple times during a nested `dispatch()` before
         * the listener is called. It is, however, guaranteed that all subscribers
         * registered before the `dispatch()` started will be called with the latest
         * state by the time it exits.
         *
         * @param {Function} listener A callback to be invoked on every dispatch.
         * @returns {Function} A function to remove this change listener.
         */


        function subscribe(listener) {
            if (typeof listener !== 'function') {
                throw new Error("Expected the listener to be a function. Instead, received: '" + kindOf(listener) + "'");
            }

            if (isDispatching) {
                throw new Error('You may not call store.subscribe() while the reducer is executing. ' + 'If you would like to be notified after the store has been updated, subscribe from a ' + 'component and invoke store.getState() in the callback to access the latest state. ' + 'See https://redux.js.org/api/store#subscribelistener for more details.');
            }

            var isSubscribed = true;
            ensureCanMutateNextListeners();
            nextListeners.push(listener);
            return function unsubscribe() {
                if (!isSubscribed) {
                    return;
                }

                if (isDispatching) {
                    throw new Error('You may not unsubscribe from a store listener while the reducer is executing. ' + 'See https://redux.js.org/api/store#subscribelistener for more details.');
                }

                isSubscribed = false;
                ensureCanMutateNextListeners();
                var index = nextListeners.indexOf(listener);
                nextListeners.splice(index, 1);
                currentListeners = null;
            };
        }

        /**
         * Dispatches an action. It is the only way to trigger a state change.
         *
         * The `reducer` function, used to create the store, will be called with the
         * current state tree and the given `action`. Its return value will
         * be considered the **next** state of the tree, and the change listeners
         * will be notified.
         *
         * The base implementation only supports plain object actions. If you want to
         * dispatch a Promise, an Observable, a thunk, or something else, you need to
         * wrap your store creating function into the corresponding middleware. For
         * example, see the documentation for the `redux-thunk` package. Even the
         * middleware will eventually dispatch plain object actions using this method.
         *
         * @param {Object} action A plain object representing “what changed”. It is
         * a good idea to keep actions serializable so you can record and replay user
         * sessions, or use the time travelling `redux-devtools`. An action must have
         * a `type` property which may not be `undefined`. It is a good idea to use
         * string constants for action types.
         *
         * @returns {Object} For convenience, the same action object you dispatched.
         *
         * Note that, if you use a custom middleware, it may wrap `dispatch()` to
         * return something else (for example, a Promise you can await).
         */


        function dispatch(action) {
            if (!isPlainObject(action)) {
                throw new Error("Actions must be plain objects. Instead, the actual type was: '" + kindOf(action) + "'. You may need to add middleware to your store setup to handle dispatching other values, such as 'redux-thunk' to handle dispatching functions. See https://redux.js.org/tutorials/fundamentals/part-4-store#middleware and https://redux.js.org/tutorials/fundamentals/part-6-async-logic#using-the-redux-thunk-middleware for examples.");
            }

            if (typeof action.type === 'undefined') {
                throw new Error('Actions may not have an undefined "type" property. You may have misspelled an action type string constant.');
            }

            if (isDispatching) {
                throw new Error('Reducers may not dispatch actions.');
            }

            try {
                isDispatching = true;
                currentState = currentReducer(currentState, action);
            } finally {
                isDispatching = false;
            }

            var listeners = currentListeners = nextListeners;

            for (var i = 0; i < listeners.length; i++) {
                var listener = listeners[i];
                listener();
            }

            return action;
        }

        /**
         * Replaces the reducer currently used by the store to calculate the state.
         *
         * You might need this if your app implements code splitting and you want to
         * load some of the reducers dynamically. You might also need this if you
         * implement a hot reloading mechanism for Redux.
         *
         * @param {Function} nextReducer The reducer for the store to use instead.
         * @returns {void}
         */


        function replaceReducer(nextReducer) {
            if (typeof nextReducer !== 'function') {
                throw new Error("Expected the nextReducer to be a function. Instead, received: '" + kindOf(nextReducer));
            }

            currentReducer = nextReducer; // This action has a similiar effect to ActionTypes.INIT.
            // Any reducers that existed in both the new and old rootReducer
            // will receive the previous state. This effectively populates
            // the new state tree with any relevant data from the old one.

            dispatch({
                type: ActionTypes.REPLACE
            });
        }

        /**
         * Interoperability point for observable/reactive libraries.
         * @returns {observable} A minimal observable of state changes.
         * For more information, see the observable proposal:
         * https://github.com/tc39/proposal-observable
         */


        function observable() {
            var _ref;

            var outerSubscribe = subscribe;
            return _ref = {
                /**
                 * The minimal observable subscription method.
                 * @param {Object} observer Any object that can be used as an observer.
                 * The observer object should have a `next` method.
                 * @returns {subscription} An object with an `unsubscribe` method that can
                 * be used to unsubscribe the observable from the store, and prevent further
                 * emission of values from the observable.
                 */
                subscribe: function subscribe(observer) {
                    if (typeof observer !== 'object' || observer === null) {
                        throw new Error("Expected the observer to be an object. Instead, received: '" + kindOf(observer) + "'");
                    }

                    function observeState() {
                        if (observer.next) {
                            observer.next(getState());
                        }
                    }

                    observeState();
                    var unsubscribe = outerSubscribe(observeState);
                    return {
                        unsubscribe: unsubscribe
                    };
                }
            }, _ref[$$observable] = function () {
                return this;
            }, _ref;
        } // When a store is created, an "INIT" action is dispatched so that every
        // reducer returns their initial state. This effectively populates
        // the initial state tree.


        dispatch({
            type: ActionTypes.INIT
        });
        return _ref2 = {
            dispatch: dispatch,
            subscribe: subscribe,
            getState: getState,
            replaceReducer: replaceReducer
        }, _ref2[$$observable] = observable, _ref2;
    }

    /**
     * Prints a warning in the console if it exists.
     *
     * @param {String} message The warning message.
     * @returns {void}
     */
    function warning(message) {
        /* eslint-disable no-console */
        if (typeof console !== 'undefined' && typeof console.error === 'function') {
            console.error(message);
        }
        /* eslint-enable no-console */


        try {
            // This error was thrown as a convenience so that if you enable
            // "break on all exceptions" in your console,
            // it would pause the execution at this line.
            throw new Error(message);
        } catch (e) {
        } // eslint-disable-line no-empty

    }

    function getUnexpectedStateShapeWarningMessage(inputState, reducers, action, unexpectedKeyCache) {
        var reducerKeys = Object.keys(reducers);
        var argumentName = action && action.type === ActionTypes.INIT ? 'preloadedState argument passed to createStore' : 'previous state received by the reducer';

        if (reducerKeys.length === 0) {
            return 'Store does not have a valid reducer. Make sure the argument passed ' + 'to combineReducers is an object whose values are reducers.';
        }

        if (!isPlainObject(inputState)) {
            return "The " + argumentName + " has unexpected type of \"" + kindOf(inputState) + "\". Expected argument to be an object with the following " + ("keys: \"" + reducerKeys.join('", "') + "\"");
        }

        var unexpectedKeys = Object.keys(inputState).filter(function (key) {
            return !reducers.hasOwnProperty(key) && !unexpectedKeyCache[key];
        });
        unexpectedKeys.forEach(function (key) {
            unexpectedKeyCache[key] = true;
        });
        if (action && action.type === ActionTypes.REPLACE) return;

        if (unexpectedKeys.length > 0) {
            return "Unexpected " + (unexpectedKeys.length > 1 ? 'keys' : 'key') + " " + ("\"" + unexpectedKeys.join('", "') + "\" found in " + argumentName + ". ") + "Expected to find one of the known reducer keys instead: " + ("\"" + reducerKeys.join('", "') + "\". Unexpected keys will be ignored.");
        }
    }

    function assertReducerShape(reducers) {
        Object.keys(reducers).forEach(function (key) {
            var reducer = reducers[key];
            var initialState = reducer(undefined, {
                type: ActionTypes.INIT
            });

            if (typeof initialState === 'undefined') {
                throw new Error("The slice reducer for key \"" + key + "\" returned undefined during initialization. " + "If the state passed to the reducer is undefined, you must " + "explicitly return the initial state. The initial state may " + "not be undefined. If you don't want to set a value for this reducer, " + "you can use null instead of undefined.");
            }

            if (typeof reducer(undefined, {
                type: ActionTypes.PROBE_UNKNOWN_ACTION()
            }) === 'undefined') {
                throw new Error("The slice reducer for key \"" + key + "\" returned undefined when probed with a random type. " + ("Don't try to handle '" + ActionTypes.INIT + "' or other actions in \"redux/*\" ") + "namespace. They are considered private. Instead, you must return the " + "current state for any unknown actions, unless it is undefined, " + "in which case you must return the initial state, regardless of the " + "action type. The initial state may not be undefined, but can be null.");
            }
        });
    }

    /**
     * Turns an object whose values are different reducer functions, into a single
     * reducer function. It will call every child reducer, and gather their results
     * into a single state object, whose keys correspond to the keys of the passed
     * reducer functions.
     *
     * @param {Object} reducers An object whose values correspond to different
     * reducer functions that need to be combined into one. One handy way to obtain
     * it is to use ES6 `import * as reducers` syntax. The reducers may never return
     * undefined for any action. Instead, they should return their initial state
     * if the state passed to them was undefined, and the current state for any
     * unrecognized action.
     *
     * @returns {Function} A reducer function that invokes every reducer inside the
     * passed object, and builds a state object with the same shape.
     */


    function combineReducers(reducers) {
        var reducerKeys = Object.keys(reducers);
        var finalReducers = {};

        for (var i = 0; i < reducerKeys.length; i++) {
            var key = reducerKeys[i];

            {
                if (typeof reducers[key] === 'undefined') {
                    warning("No reducer provided for key \"" + key + "\"");
                }
            }

            if (typeof reducers[key] === 'function') {
                finalReducers[key] = reducers[key];
            }
        }

        var finalReducerKeys = Object.keys(finalReducers); // This is used to make sure we don't warn about the same
        // keys multiple times.

        var unexpectedKeyCache;

        {
            unexpectedKeyCache = {};
        }

        var shapeAssertionError;

        try {
            assertReducerShape(finalReducers);
        } catch (e) {
            shapeAssertionError = e;
        }

        return function combination(state, action) {
            if (state === void 0) {
                state = {};
            }

            if (shapeAssertionError) {
                throw shapeAssertionError;
            }

            {
                var warningMessage = getUnexpectedStateShapeWarningMessage(state, finalReducers, action, unexpectedKeyCache);

                if (warningMessage) {
                    warning(warningMessage);
                }
            }

            var hasChanged = false;
            var nextState = {};

            for (var _i = 0; _i < finalReducerKeys.length; _i++) {
                var _key = finalReducerKeys[_i];
                var reducer = finalReducers[_key];
                var previousStateForKey = state[_key];
                var nextStateForKey = reducer(previousStateForKey, action);

                if (typeof nextStateForKey === 'undefined') {
                    var actionType = action && action.type;
                    throw new Error("When called with an action of type " + (actionType ? "\"" + String(actionType) + "\"" : '(unknown type)') + ", the slice reducer for key \"" + _key + "\" returned undefined. " + "To ignore an action, you must explicitly return the previous state. " + "If you want this reducer to hold no value, you can return null instead of undefined.");
                }

                nextState[_key] = nextStateForKey;
                hasChanged = hasChanged || nextStateForKey !== previousStateForKey;
            }

            hasChanged = hasChanged || finalReducerKeys.length !== Object.keys(state).length;
            return hasChanged ? nextState : state;
        };
    }

    function bindActionCreator(actionCreator, dispatch) {
        return function () {
            return dispatch(actionCreator.apply(this, arguments));
        };
    }

    /**
     * Turns an object whose values are action creators, into an object with the
     * same keys, but with every function wrapped into a `dispatch` call so they
     * may be invoked directly. This is just a convenience method, as you can call
     * `store.dispatch(MyActionCreators.doSomething())` yourself just fine.
     *
     * For convenience, you can also pass an action creator as the first argument,
     * and get a dispatch wrapped function in return.
     *
     * @param {Function|Object} actionCreators An object whose values are action
     * creator functions. One handy way to obtain it is to use ES6 `import * as`
     * syntax. You may also pass a single function.
     *
     * @param {Function} dispatch The `dispatch` function available on your Redux
     * store.
     *
     * @returns {Function|Object} The object mimicking the original object, but with
     * every action creator wrapped into the `dispatch` call. If you passed a
     * function as `actionCreators`, the return value will also be a single
     * function.
     */


    function bindActionCreators(actionCreators, dispatch) {
        if (typeof actionCreators === 'function') {
            return bindActionCreator(actionCreators, dispatch);
        }

        if (typeof actionCreators !== 'object' || actionCreators === null) {
            throw new Error("bindActionCreators expected an object or a function, but instead received: '" + kindOf(actionCreators) + "'. " + "Did you write \"import ActionCreators from\" instead of \"import * as ActionCreators from\"?");
        }

        var boundActionCreators = {};

        for (var key in actionCreators) {
            var actionCreator = actionCreators[key];

            if (typeof actionCreator === 'function') {
                boundActionCreators[key] = bindActionCreator(actionCreator, dispatch);
            }
        }

        return boundActionCreators;
    }

    function _defineProperty(obj, key, value) {
        if (key in obj) {
            Object.defineProperty(obj, key, {
                value: value,
                enumerable: true,
                configurable: true,
                writable: true
            });
        } else {
            obj[key] = value;
        }

        return obj;
    }

    function ownKeys(object, enumerableOnly) {
        var keys = Object.keys(object);

        if (Object.getOwnPropertySymbols) {
            var symbols = Object.getOwnPropertySymbols(object);
            if (enumerableOnly) symbols = symbols.filter(function (sym) {
                return Object.getOwnPropertyDescriptor(object, sym).enumerable;
            });
            keys.push.apply(keys, symbols);
        }

        return keys;
    }

    function _objectSpread2(target) {
        for (var i = 1; i < arguments.length; i++) {
            var source = arguments[i] != null ? arguments[i] : {};

            if (i % 2) {
                ownKeys(Object(source), true).forEach(function (key) {
                    _defineProperty(target, key, source[key]);
                });
            } else if (Object.getOwnPropertyDescriptors) {
                Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
            } else {
                ownKeys(Object(source)).forEach(function (key) {
                    Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key));
                });
            }
        }

        return target;
    }

    /**
     * Composes single-argument functions from right to left. The rightmost
     * function can take multiple arguments as it provides the signature for
     * the resulting composite function.
     *
     * @param {...Function} funcs The functions to compose.
     * @returns {Function} A function obtained by composing the argument functions
     * from right to left. For example, compose(f, g, h) is identical to doing
     * (...args) => f(g(h(...args))).
     */
    function compose() {
        for (var _len = arguments.length, funcs = new Array(_len), _key = 0; _key < _len; _key++) {
            funcs[_key] = arguments[_key];
        }

        if (funcs.length === 0) {
            return function (arg) {
                return arg;
            };
        }

        if (funcs.length === 1) {
            return funcs[0];
        }

        return funcs.reduce(function (a, b) {
            return function () {
                return a(b.apply(void 0, arguments));
            };
        });
    }

    /**
     * Creates a store enhancer that applies middleware to the dispatch method
     * of the Redux store. This is handy for a variety of tasks, such as expressing
     * asynchronous actions in a concise manner, or logging every action payload.
     *
     * See `redux-thunk` package as an example of the Redux middleware.
     *
     * Because middleware is potentially asynchronous, this should be the first
     * store enhancer in the composition chain.
     *
     * Note that each middleware will be given the `dispatch` and `getState` functions
     * as named arguments.
     *
     * @param {...Function} middlewares The middleware chain to be applied.
     * @returns {Function} A store enhancer applying the middleware.
     */

    function applyMiddleware() {
        for (var _len = arguments.length, middlewares = new Array(_len), _key = 0; _key < _len; _key++) {
            middlewares[_key] = arguments[_key];
        }

        return function (createStore) {
            return function () {
                var store = createStore.apply(void 0, arguments);

                var _dispatch = function dispatch() {
                    throw new Error('Dispatching while constructing your middleware is not allowed. ' + 'Other middleware would not be applied to this dispatch.');
                };

                var middlewareAPI = {
                    getState: store.getState,
                    dispatch: function dispatch() {
                        return _dispatch.apply(void 0, arguments);
                    }
                };
                var chain = middlewares.map(function (middleware) {
                    return middleware(middlewareAPI);
                });
                _dispatch = compose.apply(void 0, chain)(store.dispatch);
                return _objectSpread2(_objectSpread2({}, store), {}, {
                    dispatch: _dispatch
                });
            };
        };
    }

    /*
     * This is a dummy function to check if the function name has been altered by minification.
     * If the function has been minified and NODE_ENV !== 'production', warn the user.
     */

    function isCrushed() {
    }

    if (typeof isCrushed.name === 'string' && isCrushed.name !== 'isCrushed') {
        warning('You are currently using minified code outside of NODE_ENV === "production". ' + 'This means that you are running a slower development build of Redux. ' + 'You can use loose-envify (https://github.com/zertosh/loose-envify) for browserify ' + 'or setting mode to production in webpack (https://webpack.js.org/concepts/mode/) ' + 'to ensure you have the correct code for your production build.');
    }

    exports.__DO_NOT_USE__ActionTypes = ActionTypes;
    exports.applyMiddleware = applyMiddleware;
    exports.bindActionCreators = bindActionCreators;
    exports.combineReducers = combineReducers;
    exports.compose = compose;
    exports.createStore = createStore;

    Object.defineProperty(exports, '__esModule', {value: true});

})));
